Drilling tool



W. N. THOMPSON DRILLING TOOL Filed May 5l, 1935 .md f...

March 2, 1937..

Patented Mar. 2, 1.937

NUNITED STATES DRILLING TOOL Walter N. Thompson, La Habra, Calif., assignmof one-half to Jesse C. Wright, Huntington Park, Calif.

Application May 31, 1935, Serial No. 24,200

12 Claims.

This invention relates to a well drilling tool and relates more particularly to a drilling tool or drill for use in the rotary method of weli drilling. A general object of the invention is to provide a practical effective well drilling tool that is very rapid and emcient in operation.

Another object of the invention is to provide a rotary well drilling tool in the form of a drill bit or core drill embodying cutting parts that 1o cut into the formation by a percussive or chipping action.

Another Vobject of the invention is to provide a rotary well drilling bit or drilling tool that penetrates or cuts into the formation by the 15 combined action of shearing or dragging cutting `parts and chipping parts that are cooperatively related to produce a rapid penetration or the formation.

Another object of this invention is to provide a rotary well drilling tool embodying cutting parts that operate as drag type blades when the tool is penetrating certain earth formations and that operate to pound and chip away the formation as well as shear the formation by dragging when the drill encounters an earth formation that oifers greater resistance to turning of the cutting blades whereby the drill is automatically adaptable to and is eiective in penetrating earth formations of various characters.

Another object of the invention is to provide a rotary well drilling tool that embodies a cutting head that automatically retracts when the cutting parts encounter highresistance to their rotary movement and is then suddenly driven downwardly under spring pressure to chip away the formation, the sequence of dragging and chipping continuing as long as the high resistance to rotation of theA head is present.

Another object of the invention is to provide a rotary drilling tool of the character mentioned that includes cutting parts thatV are associated with the head to turn therewith and that are v held against vertical movement with respect to the barrel or shank to remain in engagement e5 with the formation during retraction of the head and thus insure the effective chipping action of the cutting parts of the head.

A further object of this invention is to provide a drilling tool of the character mentioned in which the parts are simple and inexpensive of manufacture and are readily replaceable when worn. y

The various objects and features of myv invention will be fully understood from the following detailed description of a` typical preferred form and application of the invention, throughout which description reference is made to the accompanying drawing, in which:

Fig. 1 is a side elevation of the tool provided by this invention showing the cutting head in its up or retracted position and illustrating the body and certain other parts in central vertical cross section. Fig. 2 is a transverse, detailed sectional View taken as indicated by line 2-2 on Fig. 1. Fig. 3 is an enlarged fragmentary vertical detailed sectional view illustrating the connection between one of the cutter stems and the body.` Fig. 4 is a transverse detailed sectional view taken substantially as indicated by line il-t on Fig. l and Fig. 5 is a bottom elevation of the tool..

The improved cutting means or drilling means provided by this invention is adapted forv ernbodiment in well drilling tools oi' various types, for example, it is adapted for embodiment in rotary well drills, rotary core drills, etc. In the following detailed disclosure l will describe the invention embodied in a rotary well drilling bit, it being understood that the invention is not to be restricted to this class of well tool but is to be taken as also contemplating rotary core drills.

The embodiment of the present invention illustrated in the drawing includes, generally, a shank or body l0, a head ll having cutting parts i2, means i3 for imparting downward blows or a percussive action to the head l l when the cutting parts i2 encounter high resistance to their rotation and cutting parts it rotatable with the head ll and connected with the body it to move longitudinally therewith.

The shank or body it may be varied considerably without departing from the spirit of the invention and may be varied in different applications of the invention. In the form and application of the invention illustrated in the drawing the body l0 is an elongate tubular structure. A cap or head section I5 is provided at the upper end of the body ld and has a reduced upper portion i6. The reduced upper portion i6 of the head section l5 may be internally threaded to facilitate the connection of the body with the drilling string P. In the preferred construction the wall of the body I0 is internally thickened at its lower end portion.

The cutting head Il is disposed or arranged at the lower end of the body I0 and includes a body or shoe I 1 which may be of substantially the same external diameter as the body I0. The upper end of the shoe Il may be flat and normal to oppose the lower end of the body I0 and the lower end of the shoe may be tapered or rounded downwardly and inwardly. The cutting parts I2 project downwardly and outwardly from the lower end of the shoe I1 to have active engagement with the earth formation at the bottom of the well bore. The cutting parts I2 are in the nature of blades and may be separable parts or parts that are integral with the shoe I1. The cutting blades or cutting parts I2 may be vertical and may be disposed in planes that are substantially radial with respect to the longitudinal axis of the tool. The lower cutting edges I8 of the cutting parts I2 are bevelled or sharpened to cut into the formation by a shearing or dragging action as well as by a percussive or chipping action. The lower cutting edges I3 may be straight and may be substantially horizontal as illustrated in the drawing. The reaming or outer cutting edges I9 of the cutting parts I2 are operable to ream or cut the well bore to gauge and are preferably comparatively long and substantially vertical. The upper ends of the cutting parts I2 may be bevelled or rounded upwardly and inwardly as illustrated. In accordance with the broader principles of the invention there may be any desired or practical number of circumferentially spaced cutting parts I2. In the particular form of the invention disclosed there are four equally spaced blades or cutting parts I2 on the shoe I1.

The means I3 connects or associates the cutting head II with the body I to turn therewith when there is little resistance to rotation of the cutting parts I2 and operates to impart a percussive or hammering action to the head II when there is an increased resistance to turning movement of the cutting parts I2 and I4 so that the cutting parts I2 cut or dig into the formation by a chipping action. The means I3 includes a stem 20 projecting from the upper end of the shoe I1 to enter the lower end of the tubular body I0. In the preferred arrangement illustrated in the drawing the lower end of the stem 20 is threaded into a socket 2I in the upper end of the shoe I1. The lower portion of the stem 20 is slidably guided in the lower portion of the body opening 22. The upper end portion 2(11L of the stem 2li is preferably reduced in diameter, thus providing the stem with an upwardly facing annular shoulder 23.

The means I3 includes cam parts or ratchet parts on the body IIJ and stem 20 for imparting the hammering action to the cutting head II. 'I'he thickened lower wall portion of the body I0 presents an upwardly facing internal shoulder which has a plurality of inclined or spiralled faces 24. In the particular case illustrated there are two faces 24 each extending for substantially 180, it being understood that there may be a greater number of these faces if desired. The inclined or spiralled faces 24 of the body I0 terminate at their opposite ends in abrupt or vertical shoulders 25. The shoulders 25 face rearwardly relative to the direction of rotation of the drill. The stem 20 has two downwardly facing inclined or spiralled faces 26 that are complementary to the body faces 24. 'I'he spiralled faces 26 of the stem 20 terminate at their opposite ends in abrupt or vertical shoulders 21 which face forwardly relative to the direction of rotation of the tool.

When the cutting head Il is in its lowermost position relative to the body I0 the spiralled faces 26 are in coopration with the faces 24 throughout their longitudinal extents and the shoulders 25 and 21 may be in abutment or cooperation. When the engagement of the cutting parts I2 and I4 with the earth formation causes the head I I to lag with respect to the rotating body I0 the spiralled faces 24 of the body ride along the faces 26 of the stem 20 causing the head II to retract or move upwardly with respect to the body III. The faces 24 ride or move along the faces 26 until the shoulders`25 pass the shoulders 21 whereuponthe head II is suddenly released to move downwardly relative to the body I0.

The means I3 includes a spring 30 for urging the cutting head I I downwardly relative to the body I0 to provide the desired frictional contact between the faces 24 and 26 and to move the head II downwardly with considerable force when the shoulders 25 pass the shoulders 21,r as above described, so that the cutting parts I2 strike the formation to chip or break it away. 'I'he spring 30 is in the nature oi' a heavy spiralled or helical spring surrounding the reduced upper portion 2i)HL of the stem 20. 'I'he lower end of the spring 30 may bear in an annular groove 3I in the shoulder 23. A ring 32 is "provided on the interior of the body I0 to form an abutment for the upper end of the spring 30. The ring 32 may have threaded engagement with the adjacent end portions of the b ody yIII and cap I to form a connector or coupling between the body and cap. An anti-friction bearing 33 is arranged between the upper end of the spring 3Ill and the ring 32 so that the spring 30 is subjected to a minimum amount of torque or turning forces. The opening 34 of the ring 32 may slidably guide the reduced upper portion 20B of the stem 30 and means is provided for sealing between the ring and stem as will be hereinafter described. The spring 30 acting downwardly on the stem 20 causes the spiralled faces 26 to bear on the faces 24 with considerable force so that substantial resistance to rotation of the head II is required to overcome the friction between the cooperating faces 26 and 24 and to cause slippage between them. 'I'he spring 36 is sufficiently strong to move the head II downwardly with great force when the shoulders 25 move past the shoulders 21 to suddenly free the head II for downward movement relative to the body. The resulting downward movement of the head II brings the cutting parts I2 into hammering and chipping engagement with the formation at the bottom of the well bore. j

The cutting parts I4 are associated with the head II to turn therewith and are connectedy to the body I0 in a manner so that they are made to move longitudinally therewith. The cutting parts I4 are in the form of elongate blades positioned in front of and backed up by the forward faces of the cutting parts I2. There may be one cutting part I4 at each blade or cutting part I2. The rear surfaces 3Ia of the cutting parts I4 may have sliding engagement with the forward faces 32 of the cutting parts I2. The cutting parts I4 are spaced inwardly some distance from the outer edges I9 of the cutting parts I2 and are spaced outwardly from the central longitudinal axis of the drill. The lower cutting edges 34 of the cutting parts I4 are sharpened and bevelled to have effective cutting engagement with the formation at the bottom of the well bore. The edges 34 may be straight and substantially horizontal. It is to be note'd that the cutting edges 34 of the cutting parts I4 are considerably shorter than the lower cutting edges I8 of the cutting parts I2. Flanges or guides 35 on the forward faces 32il of the cutting parts I2 have guiding engagement with the vertical edge portions of the cutting parts I4.

Sterns 36 are connected to the upper ends of the cutting parts I4 and are slidably or shiftably reu upper portion of the body opening 22.

`in its down orl lowermost position.

shoe I'I. The stems 34 are preferably removably A threaded in sockets k38 in the upper ends of the cutting parts I4. The lower end portionof the body I is externally grooved and a collar 39 is threaded on its periphery to close the outer sides of the grooves. There is thus provided an annular groove 46 -open at the lower end of the body I0 and an annular groove 4I of greater radial width at the upper end of the groove 40. The stems 36 have reduced portions 42 which extend through the groove 46 with suitable working clearance and heads 43 are provided on the upper ends of the stems to move or operate in the groove 4I. The portions 42 may be welded, pinned or otherwise secured to the bodies of the stems 36. The lower end of the body III is adapted to bear downwardly on annular shoulders 44 on the stems 36. The cutting parts I4 assembled or arranged as just described are positively urged downwardly by the body I0 and are held against upward movement with respect to the body. The 'cutting parts I4 in being connected with the head II to turn therewith may lag or remain substantially stationary with the head.

Means is provided for handling the rotary mud or circulation fluid. The upper end of the body opening 22 is open to receive the circulation iiuid conducted downwardly by the drilling string P. The stem 26 has a central longitudinal fluid passage 45 whose upper end receives fluid from the A packing gland 46 is provided on the ring 32 to prevent the leakage of uid around the stem portion 20a'. The fluid passage 45 conducts the fluid downwardly to a main passage 48 in the shoe I 1. The shoe I'I has suitable ports 49 for carrying the fluid from the main passage 48 and for discharging it at or adjacent the cutting parts I2 and I4 to flush them and to provide for the desired discharge of fluid into the lower portion of the well bore.

In operation the cap section I of the body I0 is connected t`o the lower end of the drilling string P or with the drill collar on the lower end of such a string. The ytool is operated by rotating the drilling string and feeding it downwardly in the usual manner. During operation of the tool the cutting parts I2 and the cutting parts I4 are adapted to engage and cut away the formation at the bottom of the well bore. The principal blades I2 are also operable to cut the bore to gauge. Under certain operating conditions the spring 30 may exert a sufficient downward force on the stem 20 so that the frictional cooperation between the faces 24 and 26 cause the head II to rotate with the body I0. In other words, under certain conditions the resistance to movement of the cutting parts I2 and I4 may not be sufficient to overcome thefrictional engagement between the faces 24 and 26 and the head II moves with the body IIJ. Under such conditions the cutting parts I2 act as drag type blades to shear or cut away the earth formation at the bottom of the bore. The parts are related and proportioned so that the cutting edges I8 are in substantially the same horizontal plane as the cutting edges 34 when the head II is Accordingly, under the conditions just described the bit or tool operates in substantially the same manner as the drag type cutting tools.

When the drill encounters an earth formation that offers greater resistance to forward moveformation causes the cutting head II to lag with respect to the rotating body I Il. Such lagging of the head II 4results in movement of the faces 24 along the spiralled faces 26. The cooperation of the spiralled faces 24 and 26 moves the head II upwardly thus retracting its cutting parts I2 out of active biting engagement with the formation at the bottom of the well bore.

The cutting parts I4 remain in engagement with the formation at the bottom of the bore and the drag or resistance to their rotary movement causes the head II to continue to lag relative to the rotating body I0. The spiralled faces 24 of the body Illeventually move over the faces 26 to the positionwhere the shoulders 25 pass the shou1dersv2'I. When this occurs the head I I is suddenly released for free downward movement with respect to the body I0. During the upward movement or retraction of the head II the cutting parts I4 in being connected with the body I0 by the stems 36 remain in active engagement with the formation at the bottom of the bore to cause the head II to continue to lag and to prevent, bodily downward movement of the drill. The spring 30 is further compressed during the upward movement or retraction of the head Il and upon the shoulders 25 passing the shoulders 2'I the spring moves the head II downwardly with great force. This brings the lower edges I8 of the cutting parts I2 into pounding or chipping engagement with the formation at the bottom of the bore. The cutting parts I2 may then have dragging or shearing engagement with the formation at the bottom of the bore until the resistance to forward or rotary movement of the cutting parts again causes retraction of the head I I. In some instances the head I I may be made to continue to reciprocate, in which case the cutting parts I2 out by a percussive action and have little or no dragging-cutting action. In this manner the cutting parts I2 act to cut away the formation by a shearing or dragging action and by a pounding or chipping action. The drill is thus adapted for operation in formations that are not readily penetrated by the usual drag type bits. The combined dragging and chipping action of the principal cutting parts makes the tool particularly rapid and eiicient in operation. The head II and the cutting parts I4 may be readily removed for repair or replacement. I Having described only a typical preferred form and application of my invention, I do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to myself any variations or modifications that may appear to those skilled in the art or may fall within the scope of the following claims:

Having described my invention, I claim:

1. A rotary well drilling tool including a body, a cutting head at the lower end of the body, a stem on the head telescopically assembled with the body whereby the head is reciprocable and turnable relative to the body, cutting blades on the head operable to act o n the major portion of the bottom of the well bore, means operable by virtue of the rotary drag on the blades to reciprocate the head whereby the blades have a chipping action on the formation, and a cutting part connected with the body to move vertically therewith and to turn relative thereto and engaging the head to turn with the head.

2. A rotary well 'drilling tool including a body, a cutting head, a stem on the head telescopically assembled with the body whereby the head is rotatable and reciprocable relative to the body, a cutting part associated with the head to turn .therewith having relative rotary engagement with the well bore, and means on the stem and body operable by virtue of the rotary drag on the cutting blades and the cutting part to reciprocate the head whereby the blades have a percussive cutting action.

3. A rotary well drilling tool including a body, a cutting head, a stem on the head telescopically assembled withthe body whereby the head is turnable and reciprocabie relative to the body, a cutting part associated with the head to lag and turn therewith and having relative rotary engagement with the body and being immovable vertically with respect to the body to remain in cutting engagement with the formation during reciprocation of the head, cutting blades on the to be connected with a rotary drilling string, a

cutting head at the lower end of the body reciprocable with respect thereto, cutting blades'on the head for acting on the formation at the bottom of the well bore, means for causing reciprocation of the head by virtue of rotation of the body relative to the head, a cutting part for` acting on the formation at the bottom of the well bore, means connecting the cutting part and the head for relative vertical movement and for simultaneous rotation, and means connecting the cutting part with the body for vertical movement therewith and for relative rotation whereby the cutting part turns with the head and remains in engagement with the formation during reciprocation of the head.

5. A rotary well drilling tool including a body to be connected with a rotary drilling string, a cutting head at the lower end of the body reciprocable with respect thereto, cutting blades on the head for acting on the formation at the bottom of the Well bore, means for causing reciprocation of the head by virtue of rotation of the body relative to the head, a plurality of sieparate cutting parts for acting on the formation at the bottom of the well bore and each shifta'bly bearing on the forward face of a blade, whereby their engagement with the formation may cause the head to lag relative to the rotating body, and independent connections between the body and the cutting parts whereby the cutting parts are carried by the body to remain in engagement with the formation during reciprocation of the head.

6. A rotary well drilling tool including a body to be connected with a rotary drilling string, a cutting head at the lower end of the body reciprocable with respect thereto, cutting blades on the head for acting on the formation at the bottom of the well bore, means for causing reciprocation of the head by virtue of rotation of the body relative to the head, cutting parts for acting on the formation at the bottom of the well bore shiftably bearing on the blades whereby their engagement with the formation may cause the head to lag relative to the rotating body,

and means rotatably connecting the said cutting parte with the' may and noidmgthem against vertical movement with respect to the body to remain in engagement with the formation during reciprocation of the head.

'1. A rotary well drilling tool including a body having an opening in its lower end, a cutting head at the lower end of the body, cutting blades on the head for acting on the formation at the bottom of the well bore, a stem on the head entering the opening, cam parts on the body and stem for causing reciprocation of the head by virtue of rotation of the body relative to the head, a cutting vpart bearing on and rotatable with the head, and a rotatable connection between the cutting partl and body holding the cutting part against vertical movement with respect to the body to remain in engagement with the formation and cause the head to lag relative to the rotating body.

8. A rotary well drilling tool including a body having an opening in its lower end, a cutting head at the lower end of the body, cutting blades on the headv for acting on the formation at the -bottom of the well bore, a stem on the head entering the opening, a spring in the opening acting on the stem to urge the head downwardly, cam parts on the body and stem for causing re ciprocation of the head by virtue of lagging of the head relative to the body. a cutting part rotatable with the head and associated with the head for relative vertical movement, and a rotatable connection between the cutting part and,

the body holding the cutting part against vertical movement with respect tovthe body to remain in engagement with the formation during reciprocation of the head whereby its engagement with the formation may cause the head to lag relative to the rotating body.-

9. A rotary well drilling tool including a`body having an opening in its lowern end, a cutting head at the lower end of the body, cutting blades on the head for acting on the formation at the bottom of the well bore, a stem on the head entering the opening, means for causing reciprocation of the head by virtue of turning movement of the body relative to the head comprising cooperating ratchet parts on the body and stem, and a spring in the opening urging the head downwardly, cutting parts rotatable with the head and associated with the head for relative vertical movement and means rotatably connecting the cutting parts with the body and holding the cutting parts against vertical movement with respect to the body to remain in engagement with the formation during reciprocation of `the 5 head whereby their engagement with the formation may cause the head to lag relative to the rotating body.

10. A rotary well drilling tool including a body to be connectedl with a rotary drilling string, a

tion between the last mentioned stem holding the cutting part against vertical movement and allowing it to turn with the head whereby the engagement of the cutting part with the formation may cause the head to lag.

11. A rotary well drilling tool including a body to be connected with a rotary drilling string, a cutting head at the lower end of the body reciprocable with respect thereto, cutting blades on the head for acting on the formation at the bottom of the Well bore, means for causing reciprocation of the head by virtue of rotation of the body relative tothe head when the head lags, there being an annular groove in the lower end of the body and a vertical opening in the head, cutting parts associated with the head to turn therewith, rods on the cutting parts movably received in the openings, and heads on the rodsA having an opening in its lower end, a cutting head at the lower end of the body, cutting blades on the head for acting on the formation at the bottom of the well bore, a stem on the head entering the opening, means for causing reciprocation of the head by virtue of turning mover ment of the body relative to the head when the head lags comprising cooperating ratchet parts on the body and stem, and a spring in the opening urging the head downwardly, there being an annular groove in the lower end of the body and substantially vertical openings in the head, rods shiftably received in the openings and cooperating with the body to be held against vertical movement, heads on the rods movable through the groove, and cutting parts on the rods bearing on the head whereby their engagement with the formation may cause the head to lag.

WALTER N. THOMPSON. 

